1. Field of the Invention
The present invention relates to a photographic light-sensitive element having a dyed hydrophilic colloid layer, and more particularly, to a silver halide photographic light-sensitive element having a hydrophilic colloid layer containing a basic polymer and a dye capable of being readily decolorized or removed during photographic processing.
2. Description of the Prior Art
In silver halide photographic light-sensitive elements, photographic emulsion layers and other layers are often colored in order to absorb light in a particular wavelength region.
Where it is required to control the spectral composition of light incident upon the photographic emulsion layer or layers, a colored layer is positioned in a position more remote from the support than the photographic emulsion layer or layers. Such a colored layer is referred to as a filter layer. In the case of photographic elements having a plurality of photographic emulsion layers, such as multilayer color light-sensitive elements, a filter layer may be positioned between two emulsion layers.
A colored layer is also positioned between the support and the photographic emulsion layer, or on the surface of the support opposite the emulsion side in order to prevent blurring of the image, i.e., halation, caused by re-entry, into the emulsion layer or layers, of light that is scattered during or after transmission through the emulsion layer or layers and reflected at the interface between an emulsion layer and the support. Such a colored layer is referred to as an antihalation layer. With photographic elements having a plurality of photographic emulsion layers, such as multilayer color light-sensitive elements, an antihalation layer may be positioned between two emulsion layers.
Also dyeing of one or more photographic emulsion layers is also used in order to prevent a reduction of sharpness of the image due to the scattering of light in the photographic emulsion layers. (This phenomenon is generally referred to as irradiation.)
Most of these colored layers are composed of a hydrophilic colloid and, accordingly, water-soluble dyes are usually incorporated thereinto for the purpose of dyeing these layers. Dyes to be used for this purpose must have appropriate spectral absorption properties and, in addition, must satisfy those requirements as set forth below:
(1) They must be photographically inert. That is, they must not have adverse chemical effects, such as cause a reduction in sensitivity, a regression of the latent image and a generation of fog. (2) They must be decolorized or removed by dissolving during photographic processing without leaving harmful stain on the photographic element after processing.
Much effort has been made by those skilled in the art in order to find dyes that satisfy the above requirements. Examples of hitherto known dyes include oxonol dyes containing pyrazolone nuclei, such as those described in U.S. Pat. No. 2,274,782 (corresponding to British Pat. No. 506,385), Japanese Patent Publications Nos. 22,069/64 and 13,168/68, and Japanese Patent Application (OPI) 85,130/73; other oxonol dyes such as those described in U.S. Pat. Nos. 3,247,127, 3,653,905 and 2,533,472, and French Pat. No. 1,401,588; and 4-benzylidene-pyrazolone dyes such as those described in U.S. Pat. No. 3,540,887 (corresponding to British Pat. No. 584,609).
Most of the dyes capable of being decolorized during photographic processing are decolored by sulfites present in a developing solution or by sulfites and the alkaline condition of the solution (as described, for example, in U.S. Pat. No. 2,274,782 (corresponding to British Pat. No. 506,385)).
Dyes to be used for the coloring of hydrophilic colloid layers in light-sensitive elements must have properties such that not only can they readily and completely be decolorized during photographic processings such as development, etc., but also the decolorized products thereof must be capable of being readily dissolved from the light-sensitive elements during processing steps, mainly washing steps after development, so that their color in the photographic element is not re-formed. For rapid photographic processings adopted recently in order to increase the efficiency of photographic processing, very few known dyes are satisfactory in regard to decolorizing speed during steps such as development, etc., and the dissolving speed of the decolorized products thereof or the undecolorized dyes themselves during washing steps.
On the other hand, where the dyed layer is a filter or antihalation layer situated on the emulsion side of the support, generally such a layer must be dyed selectively, so that no other layer is substantially dyed. Because, if a layer other than the filter or antihalation layer is colored, not only is the effect as a filter or antihalation layer reduced, but also harmful spectral effects are exerted on other layers. In order to selectively dye particular hydrophilic colloid layers, hydrophilic polymers containing groups having a charge opposite that of the ion of the dye are often incorporated as a mordant into hydrophilic colloid layers to be dyed, the dye being located in these particular layers in interaction between the dye molecule and the mordant.
For example, polymers derived from ethylenically unsaturated compounds having dialkylaminoalkyl ester groups such as those described in British Pat. No. 685,475; polymers obtained from the reaction of polyvinyl alkyl ketones with aminoguanidines such as those described in British Pat. No. 850,281; polymers derived from 2-methyl-1-vinylimidazoles such as those described in U.S. Pat. No. 3,445,231; and the like; are known as examples of such mordants.
However, when such a mordanting method using these polymers is employed and a layer containing dyes therein is contacted with other hydrophilic layers, a portion of the dyes often diffuses from the former layer to the latter layers. Such a diffusion of dyes depends on the chemical structure of dyes used, as well as the chemical structure of the mordants used.
When such polymeric mordants are used, dyes particularly tend to remain in the light-sensitive element after photographic processing, particularly after photographic processing carried out in a shortened period of time. It is thought that this is because such a mordant still possesses a weak bonding strength to the dye in an alkaline solution such as a developing solution, although it is considerably reduced in an alkaline solution. Such a difficulty depends greatly on the chemical structure of dyes used, as well as the chemical structure of mordants used.
Of the various known water-soluble dyes used for the dyeing of hydrophilic colloid layers in photographic light-sensitive elements, oxonol dyes having pyrazolone nuclei, which can be represented by those described in U.S. Pat. No. 2,274,782 (corresponding to British Pat. No. 506,385), have been used as useful dyes since they are capable of being readily decolorized in developing solutions containing sulfites and have only slight adverse effects on the photographic properties of photographic emulsions. Most of these dyes, however, are incapable of being mordanted sufficiently by basic polymers, so that they tend to diffuse from the basic polymer-containing layers to other layers.
On the other hand, where a colored layer is to serve as a filter layer, the absorption density of such a layer needs to be above 0.8 and, moreover, often this density must be obtained with a layer having a thickness of about 2 .mu.m or less. As a typical example of such a layer, mention may be made of yellow layers which are positioned under the blue-sensitive emulsion layer in multilayer color light-sensitive elements. In such a case, a dye that is capable of being dissolved in hydrophilic colloid layers in high concentrations must be used.